870  PRE-CAMBRIAN    GEOLOGY   OF    NORTH    AMERICA. 
not  due  to  volcanic  heat,  but  rather  to  molecular  changes  induced  by 
long-continued  pressure  of  the  immense  mass  of  superincumbent 
rocks.     The  Cerbat  Mountains  have  a  core  of  granite. 
Whitney,106  in  1865,  describes  the  Coast  Ranges,  the  region  between 
the  Canada  de  las  Uvas  and  Soledad  Pass,  and  the  Sierra  Nevada,  in 
all  of  which  regions  are  found  granitic  and  metamorphic  rocks. 
Granite  occurs  at  many  points  in  the  Coast  Ranges  and  is  described 
and  figured  as  breaking  through  the  Cretaceous  and  Tertiary  strata 
and  metamorphosing  them. 
In  the  Canada  de  las  Uvas  region,  at  San  Emidio  Canyon,  occur 
granite,  mica  slate,  syenite,  hornblende  slate,  and  limestone,  turned  on 
end  and  unconformably  overlain  by  unaltered  Cretaceous  and  Ter- 
tiary strata.  In  the  Tejon  Pass  are  found  mica  slate,  granite,  gneiss, 
and  syenite.  Near  the  fort  occurs  crystalline  limestone  associated 
with  mica  slate  and  gneiss,  together  with  magnetic  iron  ore. 
Gilbert,16  in  1875,  states  that  in  the  Inyo  Range  are  found  syenite, 
granite,  and  gneissoid  rocks.  On  its  east  face  quartzites,  siliceous 
schists,  green  schists,  and  limestones  make  the  section  more  than  1,100 
feet  thick.  In  the  Amargosa  Range  the  Whites  Peak  series  is  11,500 
feet  thick,  and  is  composed  of  quartzites,  green  garnetiferous  schists, 
and  siliceous  and  argillaceous  schists.  At  the  base  of  the  section  in 
the  Amargosa  Range  is  900  feet  of  quartzite  resting  conformably 
upon  600  feet  of  mica  schist  and  chlorite  schist.  A  section  at  Bound- 
ary Canyon  2,500  feet  thick  is  made  up  of  limestones,  micaceous  and 
other  schists,  and  quartzites.  None  of  these  rocks  are  regarded  as 
pre-Silurian.  Although  no  fossils  are  found,  the  Whites  Peak  sec- 
tion is  presumptively  Silurian. 
Marcou,167  in  1876,  states  that  granitic  rocks  occur  in  the  Sierra 
Madre  in  southern  California  at  a  number  of  points.  This  mountain 
chain  is  described  as  the  most  ancient  of  the  modern  chains  of  south- 
ern California;  that  is  to  say,  the  granite,  pegmatite,  gneiss,  and 
metamorphic  rocks  which  form  its  principal  mass  date  from  times 
anterior  to  the  Paleozoic. 
Loew,168  in  1876,  states  that  nearly  all  the  mountain  ranges  of 
southern  California  belong  to  the  Primitive  formation.  In  the  San 
Bernardino  Mountains  the  main  mass  is  granite,  accompanying  gneiss, 
mica  schist,  talcose  schist,  and  Primitive  clay  slate.  The  Riverside 
and  Halfway  mountains  consist  of  granite  and  gneiss.  At  the  Mo- 
have Range  is  a  series  of  Azoic  rocks  consisting  of  fine-grained  gran- 
ite, syenite,  hornblende  schist,  and  quartzite.  At  the  Panamint  Range 
are  Primitive  limestone  and  clay  slate  as  accompaniments  of  the 
granite.  In  the  Coahuila  Valley  eruptive  gneiss  is  found  which  has 
metamorphosed  the  limestone  on  either  side.  •  The  gneiss  shows  by 
the  position  of  its  mica  plates  a  stratification  parallel  to  the  limestone 
layers,  indicating  the  effect  of  pressure  during  the  consolidation  of 
